St Brendan's parish, Coolock

The Celtic Church did not utilise parochial structures, being primarily based around monastic settlements, but following restructuring under figures such as St. Malachy, Archbishop of Armagh, and the papal legate Cardinal Paparo in 1152, the Christian Church in Ireland was divided in the 12th century into thirty-eight dioceses, each comprising a number of parishes.

[citation needed] Shortly after formation, the Anglo-Norman invasion made changes across the whole Dublin region, and in the Reportorium Viride of John Alen, it is stated that the church at Coolock was at first in the gift of the Baron de Nugent, and later the Priory of Llanthony (near Gloucester), who held the right of presentation until the dissolution of the monasteries by Henry VIII, when the parsonage was granted to Edward Griffin and John Bathe.

One consequence of this was that it became impossible to continue to operate all the historical parishes, and at the Synod of Leinster at Kilkenny in 1614, many were grouped.

[citation needed] Until the late 17th century, the new extended Parish of Coolock was based at Artaine, notably supported by the Hollywood family, and the Church of St. Brendan at Coolock was allowed to fall into ruin, until a new Church of Ireland building was erected on its site in 1790.

[citation needed] The next priest recorded, after the Cromwellian period and the Restoration, is Richard Cahill, Parish Priest from circa 1680–1720, resident at Artaine, who arranged in 1689 for the building of the first public place of worship within the whole extended parish, a small chapel at Coolock, but who also had to say mass in private houses when anti-Catholic laws were applied more strongly.

The next known parish priest was Nicholas Gernon, who departed office in 1733, succeeded by Andrew Tuite, presiding from 1733–1771.

It is not known where the second chapel was but based on areas with and without records of such buildings, Donnelly in 1915 considered Ballymun, then part of Santry as possible; others have suggested Whitehall.

[citation needed] Terence McLoughlin was appointed as parish priest in 1771, holding office until 1785; he had already been made a canon in 1763.

During McLoughlin's time in office, the parish centre moved to Coolock, and the first surviving Parochial Registers date from this period.

Around 1810, Long was asked to take on the role of pro tem Superior and Administrator of the Irish College in Paris, which had been confiscated, along with much other British property following the French Revolution.

Work was carried out, perhaps amounting to a full reconstruction, on the chapel in 1830–1831, as it was deemed dangerous; the nave was extended and a slate roof added.

While a new church, the newer St. Assam's, had been established in nearby Raheny in 1864, Coolock itself had only the chapel left from penal times.

In 1993, the parish was placed in the care of the Marist Fathers, who operate Chanel College in Coolock, and three of their number are now (2007) its clergy.